Calipers.



No. 890,242. PATENTEDYJUNE 9, 1908.

J. H.VLONDICK. 'OALIPERS.

APPLICATION FILED AUG. 23, 1907.

a Z Q/ ff Q WITNESSES: INVEN'T'CD R'.

3md..@m JOHN l-LLQND: cm.v QMW 776 491,1

ATTORNEYS.

UNITED STATES PATENT onnron.

JOHN H. LONDIGK, OF ALMA, MICHIGAN.

OALIPERS.

Application filed August 23, 1907.

and which will instantly and accurately indicate on a dial to the thousandths of an inch or such other figures or gages as may be required for various purposes or trades, all as more fully hereinafter described and shown in the accompanying drawings, in which Figure 1 is a longitudinal section through the caliper partly in elevation. Fig. 2 is across section on line 22 Fig. 1. Fig. 3 1s a fractional elevation. Fig. 4 is an end elevation of the inner end of the handle. a detached view of the pinion.

A is a tubular handle, B a half circular extension at the inner end thereof, C the stationary jaw at the end of the extension, I) a face bottom thereon and E a sliding rod forming the movable aw.

The sliding rod extends at both ends through the handle and it is slidingly supported therein by screw-bushings a, its rear end is provided with a push knob E by means of which it may be drawn away or pushed towards the fixed jaw and it is provided upon its middle portion with a screw thread F. This screw-threaded portion is preferably made of larger diameter than the rest of the rod so that it cannot be withdrawn from the handle and means are provided to prevent the rod from turning, the drawing showing a groove b in the screw-threaded portion and guide-pin b secured in the handle and engaging into said groove.

Below the push rod and engaging with the screw-thread thereon is journaled a pinion G the teeth of which conforms to the screwthread of the push rod and forms a rack and pinion engagement therewith. The pinion is provided with cylindrical hubs c by means of which it is journaled in. a transverse open- Fig. 5 is ing formed in a cylindrical enlargement H of Specification of Letters Patent.

Patented. June 9, 1908.

Serial No. 389,778.

adjustably secured to the ends of the hubs of the pinion by means of screws 6 or otherwise and revolve therewith within the recesses. I

The parts are preferably so proportioned that the distance between the fixed and movable jaw when the latter is at its greatest distance therefrom equals one unit say one inch, and the pinion G is made to perform exactly one revolution in the travel of the push rod through this distance. Thus by dividing the circle around the disks into ten parts and by subdividing each part into four, a scale is provided in which each division represents 0.025 of an inch and in connection with a zero mark on the disk and a vernier L having twenty five divisions equaling twenty four divisions of the scale K permits thus to take accurate readings in thousandths of an inch. Both sides of the caliper may be provided with the same or differentscales, or the scale may be only on one side. I also preferably provide my caliper with means for locking the push rod, to this end I form a circular recess in the bushing a which is next to the fixed jaw. This recess is cocentric to the bushing and into it is fitted an eccentric collar N provided with an aperture corresponding to that through the bushing and adapted to register with it in one osition of the eccentric. The eccentric col ar N is provided with a handle 0 for rotating it and it will be understood that by rotating it, it will frictionally clamp the push rod in the bushing a. The handle 0 may be guided in a slot gin the bushing thus holding the eccentric in place at the same time,

Being thus constructed and arranged my caliper is simple and compact, and can be readily manipulated with one hand, the lockwing and unlocking device being within the control of the thumb and index finger of the hand holding it, besides this feature it embodies other advantages and features of construction which the expert mechanic will readily appreciate.

What 1 claim as my invention is 1. In a caliper, the combination of a frame comprising a tubular handle provided at one end with a fixed aw, bushings in the opposite ends of the handle, a push rod reciprocatingly supported in said bushings and provided intermediate said bushings with an enlarged screw-threaded portion, a pinion journaled in a transverse aperture in the frame and cooperating with the screw-threaded portion of the push rod to. form a rack and pinion engagement therewith, disks adjustably secured to the sides of the pinion and rotating therewith, there-being a circular enlargement on the handle forming recesses to receive the disks, a scale on the enlargement extending peripherally around one of the disks, the disk having an index and carrying a vernier for the scale.

2. In a caliper, the combination of a frame provided with a dial, the frame having a longitudinal bore and a transverse. bore in the center of the dial, a pinion journaled in said transverse bore and carrying the index of the dial, said pinion having hubs of larger diameter than the pinion and forming the bearings of the pinion, and a cylindrical push rod slidingly supported in the longitudinal bore of the frame, the frame being provided with removable bushings in the ends of the bore and the push rod being provided with a cylindrical enlargement engaging with the cylindrical bore of the frame,said push rod and pinion being provided with spiral teeth adapted to mesh and revolve the pinion by the endwise movement of the push rod, the teeth of the push rod being formed on the enlarged portion of the push rod and forming integral parts of a screw-thread.

3. In a caliper, the combination with the frame provided with two annular dials on opposite sides of the frame, said frame pro vided with a longitudinal bore and with a transverse bore in the center of the dials, a pinion having hubs of larger diameter than the pinion and rotatively supporting the pinion in the transverse bore, indicating disks adjustably secured to the hubs of the frame rovided with a longitudinal bore, a

cylindrical push rod in said bore, bushings in the ends of the bore forming guide bearings in which the push rod is adapted to be moved endwise and an eccentric locking collar upon the push rod seated in a recess in one of the bushings and provided with means for man ual operation, provision being made to hold the eccentric collar in its seat against endwise displacement by the movement of the push rod and to hold the push rod in position against rotative movement.

5. In a caliper, the combination with the frame having a tubular handle portion of a cylindrical push rod slidingly guided in the handle portion, screw-bushings in the ends of the handle portion forming guide bearings for the push rod, an eccentric locking collar upon the push rod seated in a recess in one of said bushings, and a finger piece on the collar for manually operating the same, the bushing being provided with a slot into which the finger piece engages.

In testimony whereof I afliX my signature in presence of two witnesses.

JOHN H. LONDICK.

. Witnesses:

JNo. H. CARPENTER, FRANK L. CoNvrs. 

